Design: Systematic review and meta-analysis of seven observational effectiveness studies
Population: 7,112 infants in Argentina, the UK and the US
Primary outcome: RSV lower respiratory tract infection hospitalisation
Effect: Effectiveness 82% (95% CI 81–82) to 3 months; 78% (70–84) to 6 months

A JAMA Pediatrics meta-analysis pooled seven post-implementation studies from Argentina, the UK and the US (2024–2025), covering 7,112 infants, 2,684 born to mothers given the bivalent prefusion F RSV vaccine (RSVpreF) in pregnancy.

When mothers were vaccinated at least 14 days before delivery, effectiveness against RSV lower respiratory tract infection admission was 82% (95% CI 81–82%) from birth to 3 months and 78% (70–84%) to 6 months, with little disagreement between studies.

This confirms in routine use what the pivotal trial showed, and supports maternal vaccination as an alternative or complement to infant nirsevimab. Timing matters: protection was measured when vaccination preceded delivery by at least two weeks. Effectiveness against intensive care and death could not be pooled. In India the vaccine's availability and place in antenatal programmes are not yet established.

Where available, offer maternal RSVpreF vaccination in pregnancy to protect infants through about 6 months
Vaccinate at least 14 days before expected delivery for the protection seen here
Ask about maternal RSV vaccination when an infant presents in the first months
Check local availability and recommendations before advising
Infants born too soon after maternal vaccination may need nirsevimab instead

Why it matters

Real-world use has matched the trial, so maternal vaccination is now a proven route to infant RSV protection.

The statistics, in plain English

Effectiveness of 82% means vaccinated mothers' infants had about a fifth of the odds of RSV admission. These were observational studies, which can overestimate effect, but the consistency (I² 0–19%) is reassuring.